Grinding mill



Get. 20, 1931. R s, |GLEHART 1,827,986

GRINDING MILL Filed Oct. 24, 1929 INVENTOR ATTORNEYS RICHARD S.

Patented Oct. '20, 1931 siren ST- A E P A 'TY IGLEHART, F srn'inerlnrn; orIIo, Asst-snort To mnnlnziurin Baornnns COMPANY, or SPRING-FIELD, 0310, aconroaa'rron. or 01110 f I F g I GRINDING ini-,

Application' filed October 24, 1929. 'seriai no. 402,254.

This invention relates to grinding mills,

I it more particularly relating to that type of 1 my invention is to soarrangethe teeth as to provide for a more effective pulverizlng action upon the material.

In the accompanying drawings:

I Fig. 1 is a partial, vertical cross-sectional View of so much of a hammer mill as is needed to illustrate my improvements.

r Fig. 2 is a fragmentary end view of my improved hammer together with some'of the associated parts. 7 f

F ig. 3 is'a reduced scale partial cross-sectional View of a typical hammer mill.

Referring to the drawings, in Fig. 3 there is shown a mill in which my improved hammers have been incorporated, 1 andi 2 representing the upper and lowercasing members connected together in any'suitable manner; The lower casing member carries in suitable bearings (not shown) a revoluble shaft 3 upon which is secured a plurality of fiat circular disks 4 having a series of openings 5 equally spaced and concentrically disposed and through which are inserted rods 6 to form the pivots for the hammers 7.

Each hammer 7 is formed of a metallic bar of hardtough steel rectangular in crosssection. These hammers are of reversible character and an opening 8 isprovided near each end to receive a rod 6 after the hammer hasbeen placed between a pair of disks 4,

thus providing a secure, loose, pivotal mounting' On rotation of the shaft the hammers fly outwardly bythe action of centrifugal force and cooperate with a curvedbreaker plate 10 secured within the upper housing 1;

the radius of curvature of the platebeing larger than that of the path of the extremities of the hammer and being so placed that the inner curved surface converges with the path of the revolving hammer but spaced therefrom at the point of nearestjapproachih as indicated at-ll infFig. 1.

The material to be ground 1s's0mumes I sufficiently small as to be able to pass through the spacell, but when fed into the mill ina manner which causes the material to flow in'a line'tangential of the path ofthe revolving;

hammers, it isthrown with great forcetowards the curved breakeriplate, fro'mwh'ich it rebounds towards the hammers, this being repeated until the material passes through the space 11- and falls on 'the perforated, screen 10 those particles which will not pass through-the screen perforationsbeing returned for further? breaking.-- i V.

[In the action ofthe hammers upon the material, the material is pulverized to better advantage and with less power requirements when-the "corners on the advancing sides of the hammers are new and comparatively? duced by forming the hammers with stepped at 'difi'erentdistances fromthe pivoted axis of the hammer, and also providing theend pivoted axis-of thehammer. In the first in- .70 sharp and attempts. have been-madeto' inp crease the volume-ofground material proends .to provide a plurality of "cutting edges V stance, dueto the fact that there are no spaces or notches betweenthe cutting edges, theopportunity' for rebound ofthe material is not present, while in the second'instance, the fact that the cutting edges are all the same distance from the pivoted axis of the hammer re-v In carrying out my invention I have so disposed the cutting'edges on the end of the V sults in' ineffective action of all but the advanced cutting edge.

the hammer 7 has a'central tooth 12 andon each side thereof a tooth 14, adjacent'teeth being separated by a pronounced recess or a notch 13. It will also be noticed that theintermediate tooth 12 is longer than the other teeth 14: so that the cutting edge thereof will be at a greater distance from the pivotal axis! of the hammer. At the side edges of the'hammer additional notches 15 are provided to form additional cutting edges 15 which are. of a less distance, from the pivotalv center- 10 than the cutting edges of the teeth 14:. From this construction it will be seen that the cutting edges being of varying distances from n the axis of the hammer which increase pro gressively reversely to the direction of rotation of the hammer, indicated by the arrow in' Fig. 1, a-more effective pulverizing action is had upon the material; and, further, due to the notches or recesses between the teeth, opportunity for rebound of the material is enhanced in heavy feeding, since small portions of the material expand intothe notches after a contact with the hammer. J r 7 These hammers are reversible both end to end and side by side to increase the lite of the hammer and forthat purposeeach end and each side thereof is constructed the same. Having thus described my invention, I claim 2' v In a grinding mill; a rotary pivoted ham-V 3 mer, the free ends "of said hammer having a central'tooth andfother teethon each side of said: central tooth. with notches between said teeth, said central tooth being 'of greater length than said other teeth, the sides of said hammer adjacent the other teeth being notched to form additional cutting edges,said additionalcutting edges being at'jalesser distance from the pivotal axis of said hammer than the cutting edges'formed on the other e0 teeth and 'the cutting edges on said central tooth being at a greater distance from the pivotal axis of said hammer than the cutting edges on the adjacent toothythe notches bea tween the teeth extendingthroughout the width thereof and being of uniform width! P In testimony whereof I have hereunto set my hand this 22nd day of October, 1929.

n RICHARD S; IGLEHART. 

